Currently, car light systems are provided with a low-beam and a high-beam option. Furthermore, some light systems are provided with a pair of fog lights so as to cope with adverse driving conditions in fog.
American patent publication US 2005/0041433 discloses a laser device for generating a laser beam which, upon incidence on a phosphor structure, produces a light beam which is collimated to a desired optical output beam by means of an optical element.
There is a need for different beam types depending on environmental conditions. As an example, special lights would be applied during the daytime and when driving in areas with public lighting. In urban areas, with their many crossings, the actual asymmetric main beam is counter-productive, particularly because additional glare is produced during acceleration after stops. Driving on motorways at a relatively high speed, with oncoming traffic traveling on a separate carriageway, requires other lighting functions. Adverse weather conditions have another impact, due to road reflection, resulting in reduced luminosity and higher (reflected) glare. In snowy, rainy or foggy weather, the emitted light is absorbed and scattered by snowflakes or water droplets so that vision is veiled by the reflected light, thereby resulting in a shorter visual range. Therefore, legislation is being formulated in order to introduce adaptive front light systems (AFS) which adapt the shape of the beam of headlights depending on exterior lighting, such as day, dawn, public lighting, night, traffic environment, such as motorways with separate carriageways, winding country roads, town and city streets, weather conditions, such as dry, wet, rainy, snowy, foggy, and/or vehicle attitudes, such as inclination changes by load, dynamic inclination changes while driving, degree of control, speed of vehicle, and ground clearance.
Mechanical AFS systems have been suggested for producing various beam shape types. As an example, International patent publication WO 2008/035267 discloses a vehicle lamp comprising a laser device and a reflector which is provided with a movable beam limiter. However, though functionality might be satisfactory, there is a need to provide light systems without moving parts, e.g. due to cost price, compactness, reliability, durability and repairability requirements.
Furthermore, AFS systems comprising multiple LEDs have been described. Due to the presence of multiple light source elements, these multiple LED systems require much space. In addition, a complex heat sink structure is needed for cooling the light source elements. As a result, the cooling performance is poor.